The present invention relates to railway couplers and more particularly to railway couplers of the type having rotatable knuckles which are operative to swing or rotate about a vertical axis into a locked position to interconnect adjoining railway cars and having an improved structure for relieving the stresses imposed on interacting elements including the coupler pin.
Rotatable knuckle type of couplers are exemplified by the American Association of Railroads (AAR) type E and F couplers. These couplers are used extensively throughout the world and include a coupler housing having upper and lower laterally extending pivot lugs. The pivot lugs are each provided with axially aligned openings and pin protector bosses which embrace opposite ends of knuckle pin about which the knuckle pivots between a coupler locked and unlocked position. In the locked position the knuckle is inter-engaged with a coupler knuckle of an adjacent railway car and it rotates to the unlocked position to release the cars from each other.
In recent years the load carrying capacity of the railway cars has been materially increased. As for example, in coal hauling cars. High stresses occur in the coupler at the pulling lugs, pivot lugs and pin protectors. Such stress causes wear to occur in the bearing surfaces of these elements and of the pin ends journaled in the pivot lugs and the associated pin protector bosses projecting from the lugs. Wear at the bearing surfaces of the pulling lugs and pin protectors permits the knuckle to translate forwardly within the coupler head and to apply shear and bending forces to the knuckle pin and the associated pin mounting structure. The design of the knuckle pin and associated mounting structure is such that it cannot be relied upon to adequately transmit and distribute the pulling forces to the coupler body.
It is an object of the present invention to provide increased bearing contact area between the knuckle and coupler head within the existing envelope to more uniformly distribute the stresses and thereby obviate the difficulties encountered heretofore.